1. Field of the Invention
The present invention relates to a high resolution display unit using a light-to-light conversion element and particularly suitable for use with optical computers.
2. Description of the Related Art
Various display units are known in which a light beam intensity-modified by a time sequential information signal is projected by a projecting optical system onto a screen to display a two-dimensional image.
In the prior display units, a light signal which is intensity-modified by each individual picture element information contained in an image signal is scanned in horizontal and vertical directions. With this arrangement, if a high intensity and high resolution optical two-dimensional image, such as a high definition two-dimensional image composed of 4000.times.4000 picture elements or pixels arranged in rows and columns should be formed nearly in real time by using a time sequential signal, the prior display units are unable to meet this request due to the absence of a suitable signal conversion element.
With the foregoing difficulty in view, the present assignee has proposed an improved display unit in which a cross-sectionally linear beam of light emitted from a light source is projected onto a photo-modulator including numeral reflective members each provided for one picture element and displaceable in accordance with a piece of picture element information. The light beam incident to the photo-modulator is intensity-modified with respect to picture elements arranged in a longitudinal direction of the linear cross-sectional shape of the light beam and then projected from the photo-modulator in the form of a cross-sectionally linear, intensity-modified beam of light. The intensity-modified light beam then impinges upon a rotating polygon mirror and is deflected by the latter in a horizontal direction at a predetermined cycle. Subsequently, the deflected light beam is projected by a projection lens onto a screen, thereby forming a two-dimensional image on the screen (see Japanese patent Application No. 1-337171 corresponding to co-pending U.S. patent application Ser. No. 63,223, filed Dec. 24, 1990).
The improved display unit is satisfactory in solving the problem associated with the prior display units described above and is able to realize a high intensity, high definition image display with utmost ease, however, it still has a problem that the action of intensity-modulation of light performed by the photo-modulator is relatively slow.